Curable fluoroelastomer compositions utilizing addition reaction of alkenyl groups and hydrosilyl groups are known in the art. Compositions of this type can be endowed with self adhesion by adding as a third component an organopolysiloxane having hydrosilyl groups and epoxy and/or trialkoxysilyl groups as disclosed in Japanese Patent No. 3239717. The composition can be cured by brief heating, and the cured product has satisfactory properties including solvent resistance, chemical resistance, heat resistance, low-temperature properties, low-moisture-permeability, and electrical properties. It is useful in an adhesion application in various industrial fields where such properties are required.
Although compositions of this type are satisfactorily adherent to metals including aluminum, stainless steel and iron, and general-purpose plastics including epoxy resins, phenolic resins and polyester resins, they are insufficiently adherent to engineering plastics such as polyphenylene sulfide (PPS) and nylons. They are not applicable where engineering plastics are used.
One method of combining an organic resin with fluoropolyether rubber is physical engagement of fluoropolyether rubber with organic resin into an integral assembly. This assembly can be disengaged by physical forces. Another method is by coating a self-adhesive fluoropolyether rubber composition to a molded resin and curing thereto. Since integral parts of resin and fluoropolyether rubber are often formed using a mold, there arises a serious problem that the fluoropolyether rubber itself adheres to the mold.
Japanese Patent No. 3324166 discloses a unique adhesive silicone rubber composition which is fully adherent to organic resins, especially thermoplastic resins, but not to metals, typically metal molds.
For the purpose of rationalizing the manufacture process, there is an increasing demand for integral molding of an organic resin and a fluoroelastomer under short-term curing conditions. It is thus desired to have a fluoropolyether rubber composition which is effectively adherent to organic resins and which is releasable from rubber-shaping metal members, typically metal molds in a practically acceptable manner.